The waterborne vessel, in one embodiment, utilizes an underwater tunnel through which passes flowing water, an ozone gas generator, an ozone plus hydroxyl radical gas generator and a source of atmospheric oxygen. A manifold mixer mixes pressurized water independently with the ozone, the ozone plus hydroxyl radical gas and the atmospheric oxygen to produce corresponding oxygenated water mixtures. Each of these oxygenated water mixtures are fed via a conduit system into the confined flow of water passing through the tunnel. A diversion channel with reverse flow channel permits super saturation of diverted flow from the primary underwater tunnel channel to provide super saturated oxygenated water with ozone plus hydroxyl radical gases and atmospheric oxygen water mixtures. A decontamination method is also provided.